The present invention relates generally to electronically controlled torque transmissions, particularly for locking automatic transmission stator assemblies.
Most actuator mechanisms, such as electromagnetic coils, vacuum actuators and hydraulic devices, are typically moved axially to produce engagement. In the case of roller clutches, engagement is typically accomplished by moving the cylindrical rollers and retainer circumferentially, such as described in U.S. Pat. Nos. 5,924,510 and 5,927,456. In order to control such a traditional roller clutch through an axially-moving actuator, it is necessary to change the direction of the actuating force. Although this change in direction could be accomplished by using a cam mechanism, such a solution is generally more complicated, expensive and less reliable. It is also possible to provide this change in direction using a combination of clutches, i.e., using a typical one-way clutch and a dog clutch. However, when there is a high speed difference between the input and output, dog clutches cannot be safely engaged.
Therefore, there is a need to provide an improved torque transmission device. It would be desirable to provide a device which will allow selective engagement of a roller clutch without requiring the rolling elements of the roller clutch to be moved circumferentially.
A primary object of this invention is therefore to provide an over-running clutch mechanism, such as that disclosed in U.S. Pat. No. 5,927,456 or U.S. Pat. No. 5,924,510, which includes an actuator which can be engaged and dis-engaged through axial movement. The device can be selectively actuated by an electromagnetic trigger clutch or by hydraulic, pneumatic or other means.
In accordance with an aspect of the present invention roller clutch utilizes a retainer that is moved axially to lock tapered rollers between cammed surfaces on the inner race and a tapered outer race. Through proper design of the cammed surfaces, a one-way or two-way clutch can be formed. Alternatively, the cammed surfaces can be formed on the ID of the outer race and the inner race can be made from a standard tapered roller bearing inner race. The invention allows selection of one of two different torque transmission modes, freewheeling or one-way (alternatively two-way) torque transmission. In order to change back and forth from the engaged and disengaged positions, the retainer is moved axially. This axial motion of the retainer can be provided by an electromagnetic coil, or alternatively a pneumatic or hydraulic actuator.